FIELD OF THE INVENTION
The present invention relates to a shockwave generating apparatus for generating shockwaves so as to disintegrate an object (calculus) to be removed present in a biological body by focused energy of the shockwaves, while displaying a shockwave effective region. The function of the instant invention may be loosely referred to as "curing" which means to remove or destroy unwanted calculus.
The present invention also relates to a hyperthermia apparatus capable of destroying a cancer tissue and the like with heating effects caused by a continuous ultrasonic wave for a removing purpose.
Various types of hyperthermia apparatuses or ultrasonic shockwave generating apparatuses capable of disintegrating an object such as a calculus, have been developed and commercially available, e.g., known from U.S. Pat. No. 4,617,931 entitled "ULTRASONIC PULSE APPARATUS FOR DESTROYING CALCULUSES" to Dory issued on Oct. 21, 1986. In this ultrasonic pulse apparatus, the ultrasonic pulse applicator with the through hole at a center position thereof is employed. Both the transducers formed in a concave shape and also the imaging ultrasonic probe are arranged in the ultrasonic pulse applicator.
This ultrasonic pulse apparatus is operable under two different functions, i.e., the ultrasonic (shockwave) apparatus and hyperthermia apparatus.
When a calculus present in a biological body under medical examination is disintegrated by employing the above-described ultrasonic pulse apparatus, a focal point or focus position of shock waves generated by utilizing the ultrasonic pulses must be positionally coincident with the calculus, which will be referred to "a focal-point positioning" in the specification. The focal-point positioning of Dory U.S. Patent is performed as follows. A B-mode image (tomographic image) of a biological body is displayed by processing B-mode ultrasonic image data acquired by the imaging probe on the display screen of the display unit, and also the focal point marker, e.g., the cross marker representative of the focal point for the shock waves or continuous ultrasonic wave is superimposed on the above-described B-mode image. Under such a display condition, this cross-shaped focal point marker is positionally made coincident with the image of the calculus on the display screen. It should be noted that this marker indicates the focal point geometrically determined by the concave surface of the destroying transducer elements. Then the focal-point positioning is properly realized.
However, the above-described conventional focal-point positioning by way of the marker superimposed on the B-mode image can merely provide positional information indicative of the peak pressure of the shockwaves, or continuous ultrasonic wave, but gives no information on the effective region, or range of these waves, in which the biological body is subjected to the medical effects caused by the shockwaves and/or continuous ultrasonic wave. That is to say, as is known in the medical field, a shape of such an effective region caused by the shockwaves and/or continuous ultrasonic wave is not a point (e.g., not a pin point), but an area with a center of this point (will be referred to as an "effective region"). A dimension of this effective region by the shockwaves and/or continuous ultrasonic wave is determined by a method for generating shockwaves and also by a diameter of an overall spherical surface formed by the removing transducer elements. The above-described difficulties of the conventional focal-point marker display method will now be described more in detail. That is, if such a focal point marker displayed on the display screen is positioned at an end portion of a biological body to be destroyed, the medical effects caused by the shockwaves or continuous ultrasonic wave may give adverse influences to a normal biological tissue around this marked end position of the biological body, and may cause harmful side effects thereon. There is another drawback that if the size of this effective region is greater than that of the object to be destroyed, the actual medical influences caused by the shockwaves or continuous ultrasonic wave may be given to the normal biological tissue around this object to be destroyed, so that the area defined by this normal biological tissue may be medically damaged. Apparently, this area is not medically damaged as long as it is viewed on the display screen. This also induces medically harm or medical unsafe treatments.
The present invention has been made in an attempt to solve the above-described drawbacks of the marking system, and therefore, has an object to provide a shockwave generating apparatus and a hyperthermia apparatus with a shockwave/ultrasonic effective region marking (patterning) system, capable of performing a safety diagnosis.